A sample collection device having a sample container and microfluidic device having one or more microfluidic circuits, the system for analyzing biological samples. The microfluidic device has a sample inlet port, a microconduit in communication with the inlet port and with reaction chamber. The reaction chamber is connected to an air vent via another microconduit. Air may be vented from the microfluidic circuit via the air vent of the microfluidic circuit via an air vent in the sample container.